According to the National Registry of Exonerations, 1900 documented exonerations have occurred in the United States since 1989, with 166 coming from California. From the national data, we have discovered that the leading causes of wrongful conviction in the United States are mistaken witness identifications, false confessions, false or misleading forensic evidence, perjury or false accusations, official misconduct, and inadequate legal representation.
The saying “all politics are local” certainly applies to the criminal justice system. Each state has its own criminal penal code, where criminal activities in one state are often legal in another. At the county level, there can also be dramatic differences. Jurors are drawn from within the county, prosecutors are often elected by the citizens of the county, resources allocated to criminal defense are decided at the county level, police departments respond to the needs and demands of their community, and thus, counties often have their own culture of patterns and practice. As the largest state in the United States, where there is now a critical mass of exonerations, it is worthwhile to look at the California exonerations not just at the state level, but at the county level, to see if there are connections between exonerations and patterns and practices in those counties.